Speedometer



J. B E R6 E SPEEDOMETER Nov. 3, 1931.

Original Filed May 16, 1921 3 Sheets-Sheet l Kiwi J. BERGE SPEEDOMETER Nov. 3, 1931.

Original Filed May 1921 3 Sheets-Sheet 2 [ll/I k m 5 L 5 f 4 I 0 5 7 v. a a .w W a l Z 0 1 i \MMIEIE 7 I=== Nov. 3, 1931. J. BERGE 1,830,503

SPEEDOMETER Original Filed May 16, 1921 3 Sheets-Sheet 3 Patented Nov. 3, 1931 llllll'lil) ATES PATENT OFFICE JOSEPH BERGE, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO A C SPARK PLUG COM- PANY, OF FLINT, I/IICHIGAN, A COIRPQEATION OF MICHIGAN SPEEDOMETER Original application filed May 16, 1921, Serial No. 470,062.

1826, Serial No. 117,562.

The present invention relates to speedometers such as are ordinarily used on motor vehicles. .In such apparatus the indicating member is usually arranged to turn on a vertical or substantially vertical axis, whereas it 15 generally essential that the driving shaft enter the speedometer casing at an angle to the vertical, and it is common practice to employ a set of bevel or other gears as the connection between the driving shaft and the r0- tating member, from which the indicating member derives its torque. Due to inaccuracies of cutting or adjustment or to wear consequent to difliculties of lubrication, the gears tend to become noisy, which is a serious objection, particularly in high grade cars. In accordance with one phase of the present invention, the gears are superseded by a flexible coupling, preferably a cable of special const u ticn, which not only runs quietly at all times, but is also inexpensive to manufacture, easily installed, and capable of giving uniform service throughout the life of the instrument.

Another phase of the invention deals with a novel and highly desirable relation of the speed indicating member in respect to the magnet and rotor, in that the parts are so arranged as to secure adjustment without varying the gap between the magnet and the magnetic mass, one of which is rotatable. In the preferred construction shown, the magnet and the mass are assembled in proper relation each to the other, .and the indicating -member is inserted more or less into the magnetic field to thereby establish the desired intensity of drag.

A ain, the invention is concerned with a particular mounting for the indicating member, whereby it is supported both from above and below, and whereby the various necessary adjustments are readily effected. This application is a division of my application, Ser.

1928 for a speedometer. This application is intended to secure protection on the specific form of speedometer illustrated in Figure 6 and Figure 7, which form employs the ring shaped magnet. The invention also provides a more simple 7 No. 470,062, filed May 16, 1921, patent- 1,670,836, May 22,

Divided and this application filed June 21, Renewed May 7, 1928.

and inexpensive rotor or armature than has been available heretofore, so far as I am informed.

The invention is further concerned with various other relations of parts and with Various details of construction hereinafter pointed out.

in the drawings:

Figure 1 is a perspective View, the casing and the magnet being omitted, and the speed indicating member, the rotor, and certain other elements being broken away to more clearly show the construction;

Figure la shows the construction of the flexible coupling or cable more clearly;

Figure 2 is a central vertical section in the plane of the flexible coupling and showing the parts assembled in the casing;

Figure 8 is a plan view corresponding to Figure 2, the casing being shown in section;

Figure l is a front elevation, parts being broken away, on a plane at the rear of the odometer Figure 5 is a section on line 55 of Figure 2;

Figure 6 is a perspective view, parts being broken away, showing a modification wherein the magnet is arranged in a horizontal, or substantially horizontal plane; and

Figure 7 is a central vertical section corresponding thereto.

1 indicates the main element of the frame, preferably of aluminum, which conforms generally to the inner surface of the back 2 of a substantially cup-shaped casin 3, hereinafter more fully described, said rame including a forwardly extending cross-wall 1 forming a bearing 5 having a vertical axis and also including a. downwardly and rearwardly inclined extension 6 forming a bearing 7 for a main hollow drive shaft 8. Connection for driving the latter from a flexible shaft 9 is made preferably by means of a non-circular end portion 10 and socket 11 with which the shafts 8 and 9 are respectively provided. The casing for the flexible shaft appears at 12 and is preferably connected with the extension 6 in the manner set forth in my United States Patent No. 1,324,787, December 16, 1919. It will be understood that the driving connection 910 permits relative longitudinal movement of the parts. At its inner end the shaft 8 is enlarged and forms a worm 15 through which odometer mechanism is driven, as will be more fully explained later. Means such as a collar 16 pressed on the shaft 8 retains the latter in its bearing.

Mounted in the bearing 5 is an upright hollow rotor shaft 20, preferably of soft iron or steel, on the upper end of which a rotor 21 is secured, preferably by press-fitting, said rotor preferably being spider-shaped with V the ends of the several arms or legs upturned at 22 so as to describe the surface of a cylinder in their travel. As will be seen from Figure 3, the angular width of any given rotor arm is preferably less than the angular distance between adjacent arms; and it is desirable also that an odd number of arms be used, so that an arm on one side of the rotor is substantially opposite the gap on the other side. Obviously, the rotor may be conveniently formed by stamping. It is desirable, in order to save space, that the arms be offset downwardly from the mid-portion of the rotor as shown. The shaft 20 may be lubricated, if desired, by a saturated felt or wicking 23 arranged to contact with the casing and to be pressed thereby against the shaft.

For driving the rotor shaft 20 from the main shaft 8, a flexible coupling 25 is preferably provided, the same being preferably formed of a steel wire core 26 surrounded by four layers each of four small similar wires 27, Figure 1a, alternately wound in opposite directions, such cable being in common use in dental machines and the like. It is desirable that the connection between the cable and the shafts 8 and 20 be of a type such as permits longitudinal movement of the cable axially of the shafts, thereby allowing the cable, by reason of its resiliency, to assume a truly circular arc and avoiding excess local stresses. Such connections may be conveniently formed by soldering the wires of the cable together at the ends (see Figure la) and fitting them into metal tips 28, substantially square in cross-section, and thereafter indenting the walls of the tips into the formed ends of the cable by means of a suitable tool, as indicated at 29. The inner surfaces of the shafts 8 and 20 are of course shaped by 'broaching or otherwise, as shown at 30, to

receive and conform to the tips 28, a slight clearance being preferably provided. In assembling, the cable is first inserted into the shaft 8, the upper end of the cable is next inserted into the bearing 5, the shaft 20 is then inserted from above into said bearing (in which process it receives the tip 28) and a collar or sleeve 31, which was initially threaded over the cable, is finally pressed upwardly onto thelower end of the shaft 20 to retain the latter in position.

It will be noted, as suggested heretofore, that the cable 25 is free to assume its natural position, there being no flexible casing such as is in universal use in flexible shafting of this nature. So far as I am informed, I am the first to employ a floating cable, such as the cable 25, as a means for transmitting driving torque between two shafts regardless of the particular instrument or association of which it forms a part, and regardless of whether the axes are inclined to each other, offset from each other, or parallel.

Supported on the frame 1 in proper relation to the rotor 21 is a magnet 35 which, in the construction shown, is of the horse-shoe type with its axis substantially perpendicular or slightly inclined to the axis of the rotor shaft 20 and with the upper end portions 36 of its legs parallel to one another (see F igure 4) The attachment of the magnet to the frame may of course vary, but this may be effected by slotting the frame, as best shown in Figure 3, and by the use of clips 37, Figure 4, fastened to the frame by screws 38. It will be evident to those skilled in the art that the magnet may be shaped and arranged otherwise than as shown, and that its axis may bear a relation to the rotor axis otherwise than the perpendicular or nearly perpendicular relation specifically set forth, one such construction being shown in Figures 6 and 7.

For purposes of manufacture and adjustment, it is preferred to form the speed indicating unit readily attachable to and detachable from the frame, as will now be described :This unit comprises, in its preferred form, a support having two lateral arms 40 provided with guide surfaces 41 coacting with corresponding surfaces 42, F igure 3, formed on the frame 1. Screws 43, threaded into the arms 40 and passing through slots 44 in the frame, Figure 1, together with a screw 45 threaded in the support and having its lower end bearing on the frame, or on a plate 46 itself inset into a slot formed in the frame, provide means for adjusting the support in a direction paralled to the axis of the shaft 20, and for securing it in any given position of such adjustment, as will be obvious. The support also comprises two forwardly extending arms 48 and 49, the latter being downwardly inclined and terminating in a cup 50 wherein a bearing jewel 51 is received. As shown, the cup projects into the hollow of the rotor shaft. The arm 48 is pierced and threaded to receive the screw 52 in the lower hollow end of which a jewel hearing 5.3 is preferably supported, and between the bearings 51 and 53 is mounted the staff or pinion 54 of the light non-magnetic oscillamagnesium is suitable for the purpose, inasmuch as it is sufliciently ductile to permit being readily drawn. The element is cut away or slotted at 56, Figure 3, throughout the greater part of its circumference to provide clearance for the arm 49, and comprises the cylindrical barrel 57 which rather closely surrounds and is coaxial with the elements 22 of the rotor. The barrel likewise turns in close proximity to the magnet so that the flux of the latter, in passing to the rotor or magnetic mass also passes through the barrel. Therefore, when the rotor is turned, the indicating element will be dragged along with a force corresponding to the speed of the rotor, being resisted by a hair spring 60 in the usual way. For convenience in adj usting thetension of the hair spring, its outer end is attached to an arm 61, the inner end of which is split at 62, Figure 3, and receives, by a spring fit, a cylindrical boss formed on the upper side of the arm 18, and a nut 63,

which serves as a lock nut for the screw 52,

and retains the arm 61 in position without interfering with the ready angular adjustment thereof by hand. In order to stiffen the indicating element, it is preferably offset downwardly and inwardly within the upper ends 22 of the rotor to form a substantially annular flange 55, best shown in Figure 2. The spoke which connects the hub of the indicating element to the flange 55 appears at 55", and is preferably reinforced by stamping a rib therein.

The intensity of drag on the indicating element is determined by its adjustment longitudinally of the parallel legs of the magnet, being greatest when the upper ends of said legs are above the upper ends of the poles 22 of the rotor a distance substantially one-half the thickness of the metal of which the magnet is made.

In the modification shown in Figures 6 and 7, the upright magnet 35 is replaced by an arcuate or C-shaped magnet 35 which has a substantially vertical axis and conforms rather closely to or surrounds the indicating element except at the front, where the numerals thereon may be read through the opening.- As a convenient means for securing the magnet in position, the frame 1 may be provided with the shelf or shelves 64; notched at 65 and bossed at 66 for the reception of the magnet and the clamping screws 67, respectively. Other things being equal, the magnet thus arranged gives increased torque per unit of sectional area over what can be secured with the construction heretofore described, inasmuch as substantially no lines of force are permitted to shunt around the rotor, but on the contrary practically all pass through its poles. By thus increasing the torque, a stronger coil spring may be used, thus giving more nearly a dead beat instrument than in the other arrangement. Otherwise than the arrangement and construction of the magnet the part-s shown in: Figure 6 are, or may be, thesame as those more specifically described in connection with Figures 1 to 5,

inclusive, and are designated by the same 1 numerals.

It is, of course, desirable that the instrument register the total and usually also the trip mileage or distance, and for this purpose odometer mechanism, the moving parts of which are designated 70 as whole, is provided, said mechanism being driven from the worm 15 through the medium of the shafts 71 and 72 and associated gearing of the worm type. As this mechanism per se forms no part of the present invention, it is not specifically described herein, such details being set forth in my companion applications S. No. 47 0,061, filed May 16, 1921, and 514,990. filed November 14, 1921, patents 1,670,835, May 22, 1928, and 1,738,558, Dec.

10, 1929'. Moreover, other odometer mechanisms than that shown may be employed. In any event, however, I prefer to make the odometer assembly as a. unit separate from the speedometer and for this purpose the odometer frame 7 3 is formed separate from the frame 1 and arranged for ready mounting thereon through the medium .of the shoulders 74 and centering bosses 75 formed on the latter, and the screws 7 6, Figure 3.

The casing may be of any suitable construction, but it is preferred that it be of steel (to relieve the magnetic field of external influences) and of the cup-shaped type. 3

The particular construction shown, together with the mounting thereof, is made the subj ect of my companion application S. N. 481,- 685, filed June 30, 1921.

As a means for lubricating the worm gearing on the shaft 71, as well as the shaft 8, a pad of saturated felt or the like encircling the shaft 8 between the worm 15 and the casing and disposed between the casing and the shaft 71,'may be employed, and for additional lubrication of the shaft 8 it may be advisable to employ a packing 81 of similar material inserted in a hole in the frame. A felt washer 82 or the like is used to seal the joint between the frame and the casing.

I claim:

1. In an instrument of the class described, a frame having a groove therein, a permanent magnet of curved horizontal outline having its poles spaced apart considerably from one another, clamping means for securing said magnet on the frame, a speed indicating element assembly adjustable vertically on the frame and including a speed indicating member the outer surface of which is visible through the opening between said ing with a dial opening, a speed cup, a ring shaped, magnet substantially coaxial with said speed cup, the poles of the ring shaped magnet being spaced to permit the visibility of the speed cup through said opening.

3. A measuring instrument, a fixed ring magnet having an interpolar gap in its circumference, a coaxial rotary speed cup therewithin, a housing enclosing said elements provided with a dial opening, the ring magnet having its poles spaced to afford visibility of the speed cup through the dial opening of the housing and between said poles.

4. In a measuring instrument, a frame, an are shaped magnet fixed in position on said frame, a rotor concentric with said magnet, a speed indicating assembly comprising a support and a speed indicating member having a spindle, the support having arms in which said spindle is journaled, one of said arms overlying the magnet, the other arm extending into the arc of the magnet, and means to adjust said speed indicating assembly relative to said magnet in the direction of the axis of said rotor.

In testimony whereof I afiix my signature.

JOSEPH BERGE. 

